John Searle is very well known for his development of a thought experiment, called the "Chinese room" argument. He set out to prove that human thought was not simply computation. His main premise is that a computational process in itself cannot have an "understanding" of events and processes. Simply put, Searle tried to show how computers do not have to understand things like a language to process information. There has been a great deal of controversy over the examples he uses to demonstrate this. In his theory, Searle describes a scenario in which a person is isolated in a room. The individual receives pieces of paper marked with Chinese characters from under the door. Even though the person does not understand Chinese, if there is a formal sorting process for the characters then they can be filed into a meaningful order. The room is supposed to be an analogy for the computer. Those who argue the point say that the analogy should hold for the entire brain. They maintain that "a person's understanding of Chinese is an emergent property of the brain and not a property possessed by any one part."[1]

each have the same propositional content, Sam smoking, yet they differ in their illocutionary force, respectively a statement, a question, a command and an expression of desire.

Searle originally assumes that the illocutionary forces of a sentence can be described as obeying specifiable rules or conditions. These rules set out the circumstances and purpose of different illocutionary acts. Searle uses four general types of rules.

Usually an illocution will have some specifiable propositional content. For instance, a request will have some future act as its content, while a statement can have any proposition as its content. Some illocutions, such as greetings, have no propositional content.

Certain background conditions are necessary for the success of each type of illocution. For instance, to successfully perform a request, it is necessary that the hearer be able to perform the requested action and that the speaker believe that the hearer can perform the action. For a greeting to be successful, the hearer and the speaker will have either just met or just been introduced. Searle called these preparatory conditions.

A greeting can be insincere. But to really thank someone, it is necessary that the speaker be sincerely appreciative, and to sincerely ask a question, the speaker has to want the answer. Searle called this the sincerity condition.

According to Searle, each illocution can be described in terms of what it is attempting to do. So an assertion counts as an undertaking that something really is the case. A question counts as an attempt to elicit some information. Thanking someone counts as an expression of gratitude. This assumed intent of the speaker, or the intentionality of the sentence, became a prime focus in Searle’s later work.

Although many think so, Searle has never proposed a clear definition of what illocutionary acts actually are. The conceptions he suggests in more or less detail vary substantially over the years (cf. Searle 1969, 1979, 1983).

Strong AI

The argument against what he calls "strong AI" is part of a broader positive position on the issue of the relations of mind and body. Searle opposes both dualism and reductionism in favor of a position he calls "biological naturalism." This view characterizes consciousness as an emergent phenomenon of the organism that is an entirely physical property (analogous to the way the pressure of a gas in a container is an emergent property of many gas molecules colliding).

Intentionality lies at the heart of Searle's Chinese Room argument against artificial intelligence which proposes that since minds have intentionality, but computational processes do not, minds cannot be intentional in virtue of carrying out computations. The whole point of the Chinese Room is to expound on the point that syntax does not imply semantics.

Intentionality

Searle next generalised this rules-based description of illocutionary force, treating it as a specific case of intentionality. In doing so he identifies a property of intentional phenomena called their direction of fit. For example, when one sees a flower, one's mental state is made to fit with the state of the world. The direction of fit is mind-to-world. But if one raises one's hand to pick the flower, one is aiming to make the world fit with one's mental state. So the direction of fit is world-to-mind.

He also develops the term Background, used here in a rather technical way, which has been the source of some philosophical discussion. Roughly speaking it is the context within which the intentional act occurs. Importantly it includes the actor's understanding of the world, including that others can and do participate in intentional activities.

Social intentionality

Searle provides a strong theoretical basis for the use of the notion of intentionality in a social context. Intentionality is a technical philosophical term meaning aboutness. Intentionality indicates that someone has attached some meaning to an object, such as a belief about it, possession of it, contempt towards it, and so on. It includes, but is somewhat larger than, the ordinary use of intent. In Collective intentions and actions Searle seeks to explain collective intentions as a distinct form of intentionality. In his previous work he has provided rules-based accounts of language and intentionality. He develops this theme by looking for a set of rules that are essential for collective intentionality.

Searle supports this analysis with five theses. The first three are:

1. Collective intentional behaviour exists, and is not the same as the summation of individual intentional behaviour.

2. Collective intentions cannot be reduced to individual intentions.

3. The preceding two theses are consistent with two constraints:

a. Society consists of nothing but individuals; there is no such thing as group mind or group consciousness.

b. Individual or group intentionality is independent of the truth or falsehood of the beliefs of the individual.

In order to satisfy these theses, Searle develops a notation for collective intentionality that links an individual intention with a collective one, but keeps the two types of intentions distinct. In effect, an individual intention can have as its outcome a collective intention.
Forming a collective intention presupposes that one understands that others can participate in the intention. Therefore:

4. Collective intentionality presupposes a Background sense of the other as a social actor – as being able to participate in collective activities.

Together, these theses lead to the claim that:

5. The theory of intentionality, together with the notion of a Background, are able to explain collective intentionality.

Constructing social reality

Searle has more recently applied his analysis of intentionality to social constructs. His interest is in the way in which certain aspects of our world come into being as a result of the combined intentionality of those who make use of them. For example, a five dollar note is a five dollar note only in virtue of collective intentionality. It is only because I think it is worth five dollars and you think it is worth five dollars that it can perform its economic function. This is so despite the apparent role of the government in backing up the value of its currency. Imagine a case in which you were attempting to make a purchase from someone who did not recognise the value of the note. Until you can convince them of its value, all you have is a coloured piece of paper. Such socially constructed objects permeate our lives. The language we use, ownership of property and relations with others depend fundamentally on such implicit intentionalities. Searle extends his analysis of social reality to the creation of institutions such as marriage and universities. He claims that the value of the five dollar note and the institution of a university are created by the function of three fundamental primitives: collective intentionality, the assignment of function, and constitutive rules.

Searle’s approach to social construction is quite distinct and divergent from those who would suggest that there is no such thing as a mind-independent reality – that what we call reality is a social construct. Towards the end of The Construction of Social Reality Searle presents an argument for realism. His arguments are not for the social construction of reality but rather construction of social reality. He claims that "all of social reality has a logical structure and that structure is linguistically constituted" in a paper titled Social Reality and Linguistic Representation.